The control of machine tools is often carried out with the aid of numerical controls, which are generally divided into three control units, an MMC operating system (Man Machine Communication) as data input and visualization unit, an SPC control unit (stored program control) and an NC (Numerical Control) control unit. Data and control commands are entered via the MMC operating system, forwarded to the NC control unit, decoded in the NC control unit, and processed further separated according to geometrical and technological data (NC control unit) and switch commands (SPC control unit). The NC and SPC control units transmit the current machine status to the MMC control unit for visualization.
Shop-floor programming and reproduction have played a major role in the machine tool field for a long time. Owing to the complexity of machining by means of machine tools, errors in the production sequence repeatedly occur. For example, during laser machining, poorly or incompletely cut workpiece parts can be produced as a result of an incorrect focal position, or, when using signing or punching tools, the imprinted signature may be too weak or too strong owing to an incorrect vertical adjustment. In that case it is necessary to produce the defective parts again in good quality once the error has been eliminated, in order to enable the machining task to be completed correctly. It is also possible for the customer to increase the required number of workpiece parts after the NC program for the machining has already been forwarded from the CAD/CAM (Computer Aided Design and Computer Aided Manufacturing) programming system to the machine tool. In order to produce these outstanding workpiece parts, the software engineer of the CAD/CAM programming system can be given the task of inserting the missing workpiece parts into a later machining task. Because machine tools often have a large number of machining tasks in the queue, it is possible that completion of the customer's order will be delayed. It is therefore important for the operator to have the possibility of shop-floor programming so that he can program and start immediate reproduction himself.
It is known from the prior art that the operator of a machine tool, in particular of a laser machine, a punching machine or a combined laser/punching machine, accesses a computer with an installed CAD/CAM programming system via a network connection and there again executes all the steps for programming a new sheet-metal plate with workpiece parts.
The operator first opens, for example, a remote desktop connection to the network computer and there starts the CAD/CAM programming system. He then indicates the type of sheet-metal plate he would like to use for the machining, that is to say the material and the thickness, and subsequently searches for the data with the geometries of the individual parts that are to be produced again. He must ensure, especially when producing very similar parts, that he selects the part with the correct dimensions. As soon as he has found the parts, he indicates how many of them he would like to produce again and nests them on the plate, that is to say arranges them on the sheet-metal plate, either manually or automatically with the aid of a nesting program in as space-saving a manner as possible. The machining steps for producing the good parts and their mode of discharge can subsequently likewise be chosen manually or automatically, that is to say it is chosen which tools, for example differently shaped punching tools and/or lasers, are used for machining the metal sheet. In the case of punching in particular, a large number of differently shaped tools can be used to produce the same good part.
The sequence of the machining is also critical, because it determines whether automatic discharge is possible or not. For example, it must be ensured that, in the last machining step, the separation of the workpiece part, that part comes to lie on a discharge flap or beneath the punching or laser head so that it can be reached by the operator or a discharge device.
When the machining sequence and the mode of discharge have been established for all the good parts, the CAD/CAM programming system generates a new NC program for reproduction. This NC reproduction program must then be transferred via the network connection from the computer of the CAD/CAM programming system to the control computer of the machine tool and started for renewed execution.
For a machine operator at the machine tool, this process can be carried out only with difficulty, because the operator in some cases has only limited operating possibilities, for example by a touch screen instead of a mouse and keyboard, and such a MMC (man-machine communication) operating system is generally also not designed for carrying out lengthy office work.
It is known from the prior art (e.g. U.S. Pat. No. 7,661,073 B2) to adapt the operating elements of the MMC operating system in order to simplify the operating modes, which are limited or executed differently than in an office computer, in their application. In EP 0642066 A1, a programming system for a machine tool was improved in that the construction of the programming system was dialogue-oriented. This simplifies the work of the operator if, for example, only a touch screen is available for inputting, or the operator is not very familiar with the complex programming system. Despite these improvements, however, an operator has for decades had to repeat substantially the complete working sequence for programming a sheet-metal plate if he wanted to prepare a new NC program for reproduction.
The system and methods described herein can advantageously make the preparation of new NC reproduction programs immediately after the actual production quicker for the operator and can reduce sources of error.